On Natural Selection, The Descent of Man, The Expression of the Emotions in Man and Animals, It Was Snowing Butterflies, The Autobiography of Charles Darwin, 1809–82, Darwin, From So Simple a Beginning: Voyage of the Beagle/Origin of Species/Descent of Man/Expression of Emotions in Man & Animals, The Origin of Species, Voyage of the Beagle, The Origin of Species/The Voyage of the Beagle